In both groups of CVD patients, endothelial dysfunction was combined with an increase in content of metalloproteinase-9 (MPP-9) in the blood, and impairment of the function of extracellular matrix, as evidenced by the increase in the levels of MMP-9/TIMP-1 complex (TIMP-1 is a tissue inhibitor of metalloproteinase) to 5.64 ± 0.16 ng/mL and 5.12 ± 0.16 ng/mL, respectively, as compared to 2.77 ± 0.12 ng/mL in healthy persons. Here, MMP9 is linked to endothelial dysfunction.